Remove obsolete dapps and update security headers (#2694)

* Embed allowed only on signer port

* Adding security headers to dapps

* Adding security headers to signer

* Removing old dapps

dapps/src/tests/authorization.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-use tests::helpers::{serve_with_auth, request};
+use tests::helpers::{serve_with_auth, request, assert_security_headers};
 
 #[test]
 fn should_require_authorization() {
@@ -76,4 +76,5 @@ fn should_allow_on_valid_auth() {
 
 	// then
 	assert_eq!(response.status, "HTTP/1.1 200 OK".to_owned());
+	assert_security_headers(&response.headers);
 }